1. Field of the Invention
The present invention relates to a parallel processing system which permits a plurality of processing units to work simultaneously at an increased speed, accordingly permitting the quick processing of a lot of information data such as in colored image processing.
2. Description of the Prior Art
As a means to make electrical interconnections of numerous processing units such as data processors or memories Japanese Patent Application Public Disclosure No.2-281359 shows a radially parallel type of bus system which comprises a stack of disks each bearing a plurality of radial signal lines of equal length radiating from its center. A corresponding plurality of CPU boards are erected and arranged around the disk stack, and are connected to the signal lines of all disks.
Disadvantageously this conventional bus system permits only two selected processing units to communicate with each other at one time, and therefore, it is inappropriate for dealing with many processing units or for permitting processing units to communicate with each other very often. In an attempt to permit many processing units to communicate with each other simultaneously the inventor proposed an improvement of such radially parallel type of bus system. As shown in FIG. 9, it includes a stack of disks 4. Each disk has an integrated circuit crossbar switch 1 fixed at its center, communication lines 3A (for instance, 16 lines), control lines 3B (for instance, 10 lines), power lines 3C and ground lines 3D all radially extending from the terminals 2 of the crossbar switch 1 and terminating on the circumference of the disk. These disks 4 are arranged vertically at regular intervals with their centers on a common axis and with all communication lines 3A, control lines 3B, power lines 3C and ground lines 3D arranged vertically in registration. Thus, a three-dimensional bus system 5 results. A plurality of longitudinal connectors 6 are attached to the circumference of the cylindrical lamination 5, and a corresponding plurality of boards 7 are applied to the longitudinal connectors 6, each board carrying an associated processor or memory, thus permitting the crossbar switches 1 to make electrical connections between selected boards 7 with the aid of a switching control (in FIG. 9), which sends control signals to the crossbar switches 1 via selected control lines 3B. This arrangement permits the simultaneous data transfer between selected processing units.
The communication lines, control lines and other different lines are terminated on the circumference of cylindrical lamination, specifically terminated with associated terminals of substantial physical size, much larger than the line. Therefore, the circumferential size of the disk must be increased with the increase of the lines printed on the disk because otherwise, a required number of terminals could not be placed on the circumference of the disk. This causes disadvantages of increasing the whole size of cylindrical lamination, and of increasing the length of communication line, and accordingly the time required for transferring data between selected processing units. Stated otherwise, the number of communication lines cannot be increased without increasing unavailable space, specifically inter-line space.